I'm not aware of any responsive framework which would be considered:
That is, if you care about how does the WebUI look on mobile devices.
AFAIK, the current deal (very lean, but not very responsive/easy for the eye theme as default) is the great solution -- if you want to and if your device is capable, you can then install theme-material which has a lot going for it.
If you're considering creating a new theme, do read this post by jow.